University of Oklahomagrid.266900.b, Department of Microbiology and Plant Biology, Norman, Oklahoma, USA.
711th Human Performance Wing, Airman Systems Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio, USA.
Appl Environ Microbiol. 2021 Nov 24;87(24):e0117721. doi: 10.1128/AEM.01177-21. Epub 2021 Sep 29.
Fungi that degrade B20 biodiesel in storage tanks have also been linked to microbiologically influenced corrosion (MIC). A member of the filamentous fungal genus Paecilomyces and a yeast from the genus Wickerhamomyces were isolated from heavily contaminated B20 storage tanks from multiple Air Force bases. Although these taxa were linked to microbiologically influenced corrosion , precise measurement of their corrosion rates and pitting severity on carbon steel was not available. In the experiments described here, we directly link fungal growth on B20 biodiesel to higher corrosion rates and pitting corrosion of carbon steel under controlled conditions. When these fungi were growing solely on B20 biodiesel for carbon and energy, consumption of FAME and -alkanes was observed. The corrosion rates for both fungi were highest at the interface between the B20 biodiesel and the aqueous medium, where they acidified the medium and produced deeper pits than abiotic controls. Paecilomyces produced the most corrosion of carbon steel and produced the greatest pitting damage. This study characterizes and quantifies the corrosion of carbon steel by fungi that are common in fouled B20 biodiesel through their metabolism of the fuel, providing valuable insight for assessing MIC associated with storing and dispensing B20 biodiesel. Biodiesel is widely used across the United States and worldwide, blended with ultra-low-sulfur diesel in various concentrations. In this study, we were able to demonstrate that the filamentous fungus Paecilomyces AF001 and the yeast Wickerhamomyces SE3 were able to degrade fatty acid methyl esters and alkanes in biodiesel, causing increases in acidity. Both fungi also accelerated the corrosion of carbon steel, especially at the interface of the fuel and water, where their biofilms were located. This research provides controlled, quantified measurements and the localization of microbiologically influenced corrosion caused by common fungal contaminants in biodiesel fuels.
在储存罐中降解 B20 生物柴油的真菌也与微生物影响的腐蚀（MIC）有关。从多个空军基地的重度污染 B20 储存罐中分离出了丝状真菌拟青霉属和酵母属威克汉姆酵母属的一个成员。尽管这些分类群与微生物影响的腐蚀有关，但没有对其在碳钢上的腐蚀速率和点蚀严重程度进行精确测量。在本研究中，我们直接将真菌在 B20 生物柴油上的生长与在受控条件下碳钢的更高腐蚀速率和点蚀腐蚀联系起来。当这些真菌仅在 B20 生物柴油上生长以获取碳和能源时，观察到 FAME 和-α烷的消耗。这两种真菌的腐蚀速率在 B20 生物柴油与水介质的界面处最高，在那里它们使介质酸化，并产生比非生物对照更深的点蚀。拟青霉对碳钢的腐蚀最大，产生的点蚀损伤最大。本研究通过真菌对燃料的代谢来表征和量化常见于污染 B20 生物柴油中的真菌对碳钢的腐蚀，为评估与储存和分配 B20 生物柴油相关的 MIC 提供了有价值的见解。生物柴油在美国和全球范围内广泛使用，与超低硫柴油以各种浓度混合。在本研究中，我们能够证明丝状真菌拟青霉 AF001 和酵母威克汉姆酵母 SE3 能够降解生物柴油中的脂肪酸甲酯和烷烃，导致酸度增加。这两种真菌还加速了碳钢的腐蚀，特别是在燃料和水的界面处，它们的生物膜位于此处。这项研究提供了受控的、量化的测量结果，并定位了生物柴油燃料中常见真菌污染物引起的微生物影响的腐蚀。
